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The hdd from my server died for 4 weeks ago. Bought a new one and installed
debian 3.0r1. When I want to load the firewall from a remote ssh client the
connection dies (PuTTY). So I added a monitor and a keyboard to the server
and again I loaded the firewall. It wents fine, but from that point I can't
ping the server anymore, a remote login isn't anymore possible, only after a
reboot. If I do a portscan at the ports 1-1024 after the reboot the result
is:

Starting nmap V. 2.54BETA31 ( www.insecure.org/nmap ) Interesting ports on
h231002.upc-h.chello.nl (62.194.231.2): (The 1010 ports scanned but not
shown below are in state: closed)
Port       State       Service
9/tcp      open        discard
13/tcp     open        daytime
22/tcp     open        ssh
25/tcp     open        smtp
37/tcp     open        time
111/tcp    open        sunrpc
113/tcp    open        auth
135/tcp    filtered    loc-srv
137/tcp    filtered    netbios-ns
138/tcp    filtered    netbios-dgm
139/tcp    filtered    netbios-ssn
445/tcp    filtered    microsoft-ds
515/tcp    open        printer
1024/tcp   open        kdm

Before the crash the list with open ports was much shorter. I think it has
to do with the package ipmasq wich is installed too, or a _supervisor
firewall_ . But when I remove ipmasq, the computers behind the server can't
go on the Internet.

Does someone know why the firewall doesn't work and how to fix this?

HTH,

-WJ

Windows: Where do you want to go today?
MacOS: Where do you want to be tomorrow?
Linux: Are you coming or what?
echo -n "IPTables Firewall."
IPTABLES="/sbin/iptables"

#FLUSH
echo -n "Flush all tables."
$IPTABLES --flush
echo -n "."
$IPTABLES --table nat --flush
echo -n "."
$IPTABLES --delete-chain
echo -n "."
$IPTABLES --table nat --delete-chain
echo ". done"

echo -n " Setting up masquerading rules."
# Set up IPFORWARDing and Masquerading
$IPTABLES --table nat --append POSTROUTING --out-interface eth1 -j MASQUERADE
echo -n "."
$IPTABLES --append FORWARD --in-interface eth1 -j ACCEPT
echo ". done"

echo -n "Setting rules for loopback device."
# Allow loopback access.
$IPTABLES -A INPUT -i lo -p all -j ACCEPT
echo -n "."
$IPTABLES -A OUTPUT -o lo -p all -j ACCEPT
echo -n "."

echo -n "Setting rules for eth0 device."
# accept established connections
$IPTABLES -A INPUT -i eht0 -m state --state ESTABLISHED,RELATED -j ACCEPT
echo -n "."
#$IPTABLES -A INPUT -p tcp --tcp-option ! 2 -j REJECT --reject-with tcp-reset
#echo -n "."
$IPTABLES -A INPUT -p tcp -i eth0 --dport 21 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p udp -i eth0 --dport 21 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p tcp -i eth0 --dport 22 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p udp -i eth0 --dport 22 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p tcp -i eth0 --dport 25 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p udp -i eth0 --dport 25 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p tcp -i eth0 --dport 80 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p udp -i eth0 --dport 80 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p tcp -i eth0 --dport 110 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p udp -i eth0 --dport 110 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p tcp -i eth0 --dport 65500:65535 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p udp -i eth0 --dport 65500:65535 -j ACCEPT
echo -n "."
$IPTABLES -A INPUT -p icmp -i eth0 -j ACCEPT
echo ". done"

echo -n " Setting rules for eth1 device."
# Accept all incoming connections
$IPTABLES -A INPUT -i eth1 -p all -j ACCEPT
echo ". done"

echo -n " Drop all other connection attempts."
$IPTABLES -P INPUT DROP
echo ". done"

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